A driver assistance system (DAS) monitors the surrounding environment of an automotive vehicle and provides feedback to the driver to warn about a potentially hazardous event that may occur if the driver does not take corrective action.
In a typical DAS commercially available today, a camera is mounted to the front windshield of a vehicle to monitor a region forward of the vehicle. The camera is connected to an image processor or digital signal processor which is programmed to analyze the images obtained by the camera and determine whether or not a predefined probability event exists. For example, the image processor may track objects in the field of view, estimate the distance to each object and determine whether or not the trajectory of the vehicle lies in the path of the object. In the event the vehicle is heading towards a given object and the distance between the vehicle and the given object is less than a predefined threshold, the image processor may recognizes this situation as a ‘forward collision’ probability event and send a forward collision alert (FCA) to the driver. The alert may be provided in a number of different ways depending on the DAS system in question, such as an audible sound, or a momentarily application of the brakes or automatically turning off a cruise control.
Similarly, the image processor may analyze the lane markings on the roadway to determine if the vehicle is heading towards and touches or is within a certain distance of the edge of the lane marking for a certain time when the turn signal is not activated. In this case the image processor may recognize this situation as a ‘lane departure’ probability event and alert the driver that he or she is unintentionally veering out of the current lane and provide a lane departure warning (LDW) to the driver such as a vibration or tug in the steering wheel.
There are a variety of other DAS systems that have been deployed commercially which use optical cameras, radar, or ultrasonic sensors to sense a spatial region external to the vehicle. Examples of other DAS systems are ultrasonic backup warning systems, which warn the driver of a potential obstacle in the path of the vehicle when the vehicle is placed in reverse and provide a louder and louder chime as the vehicle gets closer to an obstacle; radar based side collision systems, which scan the blind spots of the vehicle that are not viewable by the external side mirrors to warn of another vehicle in the blind spot by flashing a light or lamp in the external side view mirror; or camera based high beam systems, which determine whether or not the vehicle is close enough to another vehicle so as to alert the driver or automatically control for the driver the application of the low beam and high beam lights.
In each of these cases, the developers of the DAS system most likely tested their systems to ensure that the DAS system met certain objectives. Nevertheless, it would be beneficial to know just how useful such DAS systems are to the public at large. Do they in fact work well under real world conditions? Is the extra cost of such systems justified because they save lives? Should such systems be made mandatory? Or is the efficacy of such systems only marginal because they raise too many false positives that are ignored by drivers?
The first step in answering such questions entails the necessity of collecting useful statistical information with respect to the efficacy of the DAS employed in the automotive vehicle. This leads to the problem of what data to collect, and how to collect it given that the DAS has to continuously monitor certain data that the system must analyze while needing to retain certain data for statistical purposes. The limited memory storage capacity of vehicle control system(s) is also a problem.